There is overwhelming evidence of racial disparities in health care and mounting evidence of disparities for other traditionally disadvantaged or stigmatized groups. Physician behavior and decision-making are documented contributors to disparities in care. Studies examining why well-intentioned and egalitarian physicians' provide unequal care point to the role of implicit (automatic, unconscious) biases, which have been shown to affect physicians' clinical decision-making, interpersonal processes of care, and to directly affect patient trust and subsequent adherence. Furthermore, medical students and physicians have been found to have high levels of implicit bias towards sexual minority and obese individuals that are likely to contribute to documented disparities in care for these groups. The proposed renewal builds on an unprecedented longitudinal study involving a rich dataset collected from a cohort of over 3959 medical students in their 1st and 4th year of medical school who were enrolled in the Medical Student CHANGES Study (1 R01 HL085631, Contributors to Racial Bias in Medical Student Judgment and Decision-Making). In Medical Student CHANGES we found that specific activities in the formal curricula, negative role-modelling, interracial contact, and diversity climate all predicted change in implicit racial bias between the 1st and 4th years of medical school. The proposed renewal uses a longitudinal repeated measures design to assess the impact of residency experiences among this cohort, independently and in combination with individual and medical school factors, on: 1) racial, obesity and sexual orientation biases and 2) attitudes and behavior that have been shown to protect from, or exacerbate, the impact of bias on clinical behavior and decision-making. The proposed renewal will serve as a much-needed and entirely novel examination of the effect of residency training, climate and informal and formal norms on racial, sexual orientation, and obesity bias in new physicians. In addition to adding to our understanding of how residency affects bias, it will provide insight into the way residency influences new physician behavior shown to reduce the impact of biases on behavior and decision-making. Last, it will allow for disentangling the effect of individual, medical school, and residency factors so that more effective interventions can be developed. This renewal proposal is part of a program of research intended to evaluate and improve the degree to which physician training promotes physicians' ability to provide equally high quality and patient-centered care to diverse patients. To our knowledge, this is the first longitudinal study of this scope that investigates changes in medical trainees' social attitudes and experiences that can directly influence the quality of medical care they will provide to members of historically stigmatized groups. Understanding the factors that shape medical physician trainees' beliefs and attitudes across their medical training will provide unique information for new interventions that can promote more effective healthcare for traditionally disadvantaged or stigmatized groups.